Shares of homebuilders also were set to surrender some gains from Monday's rally after Credit Suisse downgraded a group of industry leaders on concerns that prices will continue to fall and credit standards will remain tight. Toll Brothers shares fell more than 2 percent while KB Home fell 3 percent premarket.

At the same time, Apple shares gained nearly 1 percent in premarket trading as the company prepares a new product rollout, widely believed to be the debut of new new iPods.

Dow component Hewlett Packard also was among the early gainers, with shares picking up 2 percent premarket after Bernstein upgraded it following HP's acquisition of Electronic Data Systems.

The price of oil remained depressed as OPEC powerhouse Saudi Arabia suggested that a meeting of oil ministers of the 13-nation organization will decide to keep crude production steady, despite their worries over rapidly falling prices.

At the same time, common shares for Fannie climbed 16 percent and Freddie gained more than 6 percent.

On the economic front, a measure of U.S. employment expectations fell to its lowest level since 2003, amid signs the job market slowdown is spreading to economies around the globe, a quarterly survey by Manpower showed.

Pending home sales data are due at 10 am New York time and are expected to have fallen by 1.4 percent in July compared with a 5.3 percent rise in June. At the same time, wholesale inventories data will be released and are expected to have risen by 0.7 percent in July versus 1.1 percent in June.